Age Only

If you look at the settings on the "About" section of your profile, you'll note that you only have three options with regard to showing your age: Show both your birth date and age; show only your birth date; or show nothing. But what about a fourth option? Show only your age. If there's the option of showing just your birthday without your age, why not the opposite? I understand how the already existing options are used, like if you don't want people to know how old you are. But what if you don't mind people knowing your approximate age, but just not your exact birth date? Like perhaps if you don't want a bunch of "happy birthday" comments on your profile.

That's my proposal. Even if you might not use such an option, don't you think it's an option we should have? Comments are welcome!